Preswirl guide device

ABSTRACT

The preswirl guide device for generating a preswirl in the intake region of a compressor comprises a multiplicity of guide vanes, which are pivotable about a respective vane shank connected to the guide vane, and a pivotable adjusting ring and adjusting levers for transmitting torque from the adjusting ring to the vane shank of each guide vane. The vane shank and the adjusting lever of the respective guide vanes are of one-piece design. The casing in which the guide vanes are rotatably mounted consists of at least two parts joined together in the region of the bearings of the guide vanes. Due to the one-piece design of the guide vane, the number of components to be fitted is reduced. This simplifies the fitting and possible service work on the guide device.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to EP Application06405137.8 filed in Europe on Mar. 31, 2006, the entire contents ofwhich are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The disclosure relates to the field of turbomachines to which exhaustgases of internal combustion engines are admitted. A guide device isdisclosed for generating a preswirl in the intake region of a compressorand an exhaust gas turbocharger having such a preswirl guide device.

BACKGROUND INFORMATION

Exhaust gas turbochargers are used for increasing the output of internalcombustion engines. In modern internal combustion engines, theadaptation of the exhaust gas turbocharger to variable operatingconditions is becoming more and more difficult. What is referred to asthe variable turbine and/or compressor geometry offers a widespreadpossibility in this respect. In the variable turbine geometry, the guidevanes of the distributor upstream of the turbine wheel are oriented moreor less at a steep angle to the flow in accordance with the powerrequirement of the turbine. In the variable compressor geometry, theguide vanes in the diffuser downstream of the compressor wheel areoriented more or less at a steep angle to the flow.

A further possibility for adapting the exhaust gas turbocharger to thevariable operating conditions is offered by preswirl guide devices,which in the intake region of the compressor generate a certain preswirlin the drawn-in air or possibly in the drawn-in air/fuel mixture, in amore or less pronounced manner depending on the operating point, in thedirection of rotation of the compressor wheel or in the oppositedirection.

In conventional preswirl guide devices, as are known, for instance, fromDE 36 13 857 A1, the vanes are mounted in a casing which is in one piecein the bearing region. To this end, the vanes must be secured by anadditional bearing bush, and the adjusting lever must be designed so asto be separable for fitting reasons. This may lead to additional costsand tolerance errors and may considerably reduce the reliability duringoperation.

SUMMARY

A preswirl guide device is disclosed which can function reliably for along operating period, is simple to fit and has adjustable guide vanes.

An exemplary preswirl guide device for generating a preswirl in theintake region of a compressor comprises a plurality of guide vanes whichare pivotable about a respective vane shank connected to the guide vane,the vane shanks and therefore the axes of rotation of the guide vanesbeing oriented essentially perpendicularly and radially relative to theshaft axis of the compressor. Furthermore, the exemplary preswirl guidedevice can comprise an adjusting ring, arranged coaxially to the shaftaxis of the compressor and pivotable about this axis, and an adjustinglever for transmitting torque from the adjusting ring to the vane shankof each guide vane. The vane shank and the adjusting lever of each guidevane can be of one-piece design.

Due to the one-piece design of the guide vane, the number of joints canbe reduced, which can have a positive effect on the material wear. Inaddition, the number of components to be fitted can be reduced. Thissimplifies the fitting and possible service work on the guide device.

The casing of the exemplary preswirl guide device, in which casing theguide vanes can be rotatably mounted, comprises at least two partsjoined together in the region of the bearings of the guide vanes.

This can permit the fitting of the guide vane designed in one piece withintegrated adjusting lever, and in addition it is thereby possible tomount and secure the vane with the bearing point in the axial directionwith respect to the axis of rotation of each guide vane. To improve thewear resistance, the bearings can be protected with inserted bearingsleeves.

This axial mounting of the guide vanes can be effected via projectionson the vane shanks and on the casing surrounding the vane shanks. Theseprojections extend in the radial direction with respect to the axis ofrotation of the guide vane. The projections engage one inside the otherfor the axial mounting of the guide vane.

Additionally or alternatively, grooves may also be incorporated in thecasing and/or in the vane shanks, said grooves interacting withcorresponding projections for axially securing the guide vane. Ifgrooves are incorporated in both the casing and the vane shanks, theaxial mounting may be effected with special bearing rings which arearranged in the grooves. The grooves and the projections may also extendonly partly around the respective vane shank.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments are explained in detail below withreference to drawings, in which:

FIG. 1 shows a section through a first exemplary embodiment of apreswirl guide device having a central body held by means of a retainingrib,

FIG. 2 shows an isometric detailed view of the exemplary preswirl guidedevice according to FIG. 1,

FIG. 3 shows a section through a second exemplary embodiment of apreswirl guide device,

FIG. 4 shows an isometric detailed view of the exemplary preswirl guidedevice according to FIG. 3,

FIG. 5 shows an enlarged detail of the section in FIG. 1 in the regionof the guide vane shank, with a detailed illustration of a firstexemplary axial mounting of the guide vanes,

FIG. 6 shows the enlarged detail of the section in FIG. 1 in the regionof the guide vane shank, with a detailed illustration of a secondexemplary axial mounting of the guide vanes,

FIG. 7 shows an enlarged detail of the section in FIG. 1 in the regionof the adjusting lever, with details of the mounting of the adjustingring,

FIG. 8 shows a section through an exemplary preswirl guide device havinga central body held by the guide vanes, and

FIG. 9 shows a detail with an alternative variant of the secondexemplary embodiment, according to FIG. 3, of the preswirl guide device.

DETAILED DESCRIPTION

FIG. 1 shows a section through a guide device in the intake region of acompressor. As described at the beginning, such compressors are used inexhaust gas turbochargers for increasing the output of internalcombustion engines. The arrows in the figure indicate the flow path ofthe medium to be compressed, which can be air or possibly an air/fuelmixture for the combustion process in the internal combustion engine. Inaddition, such guide devices can be used in any type of compressor, forexample in industrial compressors driven by electric motors.

The guide device comprises a plurality of guide vanes 10 arranged so asto be oriented in the radial direction with respect to the compressoraxis. Each of the guide vanes comprises, in addition to the vane profile11 projecting into the flow duct, a vane shank 12 with which the vaneprofile can be rotatably mounted in a casing. The vane profile can berotated about the axis of the vane shank via an adjusting lever 13. Anadjusting ring 30 which is arranged concentrically to the axis of thecompressor is provided in order to drive the adjusting lever and thusadjust the vane profile. All the vanes can be adjusted simultaneouslyabout the respective axes of their vane shanks by rotating the adjustingring 30.

In a first exemplary embodiment according to FIGS. 1 and 2, the torquetransmission from the adjusting ring 30 to the vane shank 12 can beeffected via a ball head 14 arranged on the free end of the adjustinglever 13. The ball head 14 can be guided in a groove 31 of the adjustingring, said groove 31 having two walls running parallel to one another.In the groove, the ball head can have the translatory and rotary freedomof movement necessary for realizing the torque transmission. In order toachieve a uniform distribution of pressure over a large area in thecontact region between ball head and groove wall and thus reduce thewear of the parts pressing on one another, the surface acting on theball head of the adjusting lever for transmitting the torque from theadjusting ring to the vane shank of each guide vane can be designed likea ball socket. In this case, the ball socket is formed at least partlyfrom a sliding shoe 20 arranged to be displaceable in a translatorymanner. If the adjusting ring 30 is rotated for adjusting the guidevanes, the sliding shoe 20 is displaced by the ball head 14 in thegroove 31 in the plane of the groove walls. If the adjusting ring isrotated, the position of the adjusting lever changes relative to theadjusting ring. In addition to the translatory displacement of thecenter of rotation of the ball head inside the groove, the adjustinglever rotates relative to the adjusting ring. The translatorydisplacement of the center of rotation of the ball head can be madepossible by the sliding shoe sliding along the groove walls, whereas forthe rotation the ball head can rotate in any desired direction in theball socket formed by the sliding shoe. The sliding shoe may also be oftwo-piece design by a ball socket half having a flat, slidable rear sidebeing arranged on each side of the groove in the adjusting ring.

In a second exemplary embodiment according to FIGS. 3 and 4, the torquetransmission from the adjusting ring 30 to the vane shank 12 can beeffected via a cylindrical pin 15 arranged on the free end of theadjusting lever 13. The pin engages in a hole of a cylindrical slidingelement 21 mounted in the adjusting ring 30 likewise in a hole 32. Thesliding cylinder 21 can be rotated about its own axis in the hole 32 andcan be displaced along its own axis. The hole in the sliding cylinder,this hole being provided for accommodating the pin 15, can beperpendicular to the axis of the sliding cylinder. The pin can berotated about its own axis in this hole and can be displaced along itsown axis. This again provides for the freedom of movement necessary forrealizing the torque transmission, in each case in a translatory androtary manner at two locations. Alternatively, the pin 15, as shown inFIG. 9, may be fixed in the sliding cylinder 21 and may be mountedinstead in a sliding manner in a corresponding hole in the free end ofthe adjusting lever 13 of the guide vane.

Instead of the illustrated exemplary embodiments described in moredetail, further exemplary embodiments for torque transmission areconceivable, for instance having an adjusting lever which is designed asa toothed wheel segment and engages in the adjusting ring provided witha toothed rim. The vane profile 11, the vane shank 12 and the adjustinglever 13 together with the top part necessary for the torquetransmission, that is to say the ball head 14 or the pin 15, can beformed in one piece. This means that the entire guide vane 10 with itsfunctional components can be cast or milled in one piece or elseassembled from a plurality of parts in a frictional, positive-locking orintegral manner to form one piece before fitting into the casing. Forexample, the vane profile, the vane shank and the adjusting lever can becast as one piece and then the ball head or the pin driven with aninterference fit into an opening, provided for this purpose, in theadjusting lever or else loosely inserted and welded or cast in place.

So that the guide vane of one-piece design can be inserted into theaperture provided for it in the casing, the casing can be split in theregion of the bearing points of the guide vanes.

As can be seen from FIG. 2, at least two casing parts 41 and 42 whichcan be joined together in the axial direction with respect to thecompressor axis can be provided. In the region of the bearing point ofeach guide vane, the two casing parts jointly form the aperture 45. Thetwo casing parts 41 and 42 can be held together, for example, withconnecting elements in holes 46 provided for this purpose or via othersubsequently installed casing parts.

When the casing is split in the region of the guide device, the mountingof the guide vanes and of the adjusting ring can be greatly simplified.As shown in FIG. 5, the vane shank can thus be secured in the axialdirection in a simple manner on radially projecting casing edges 49,instead of with an additional bearing bush or with external bearingpoints. These casing projections 49 may be provided on both sides or onone casing part in each case at the axial ends of the bearing point ofthe vane shank. Additionally or alternatively, as shown in FIG. 6, agroove extending over at least part of the circumference in the aperturebetween the two casing parts 41 and 42 can accommodate a projection 17likewise extending over at least part of the circumference of the vaneshank. Instead of a groove in the casing parts, the groove may also beincorporated in the vane shank in another variant and the casing partsmay be provided with a corresponding projection. In a further exemplaryembodiment, a groove can be incorporated in one casing part, whereas theother casing part has a projection and accordingly the vane shank isprovided with a respective projection and a respective groove. Therotatability of the guide vanes can also be limited in a simple mannerby means of a groove that does not extend over the full circumferenceand a projection that extends over an even smaller part of thecircumference. In a further exemplary embodiment, grooves can beincorporated in both the vane shank and the casing surrounding it. Inthis variant, a bearing ring arranged in the grooves provides for theaxial mounting of the guide vanes. All these exemplary embodiments ofthe internal axial mountings can enable the axial play of the guidevanes to be reduced. To improve the sliding property in the bearingregion of the guide vanes or prevent wear, the bearing components, thatis to say the casing parts and/or the vane shank, may be hardened orprovided with a coating of an abrasion-resistant material.

As shown in FIG. 7, the axial and radial mounting of the adjusting ringcan likewise be realized in a simple manner. Before the casing parts 41and 42 are pushed together in the axial direction, the adjusting ring 30can be arranged together with the guide vanes between the casing partsor on one of the two casing parts. When said casing parts are pushedtogether, the final orientation of the adjusting ring in the axialdirection is then effected automatically. In this case, the adjustingring 30 can be mounted in the axial direction from both sides by acorresponding bearing element 47′ and 47″. As can also be seen from FIG.2, the first axial bearing element 47′ is part of the first casing part41, whereas the second axial bearing element 47″ is part of the secondcasing part 42. The radial mounting of the adjusting ring can beachieved in a simple manner by seating the adjusting ring on acircumferential projection 48.

As at the bearing point of the guide vane, the bearing parts of theadjusting ring may also be hardened or coated.

According to one exemplary embodiment of the guide device, a centralcasing body can be optionally arranged in the central region of theguide device, in which central region the tips of the plurality of guidevanes meet. This central body lies concentrically on the axis of thecompressor. The central body is part of the casing, which in the regionof the guide device forms the flow duct of the medium to be compressed.

As shown in FIG. 1, the central body 44 can be positioned and held inplace via one or more radially running casing ribs 43.

In order not to have to impair the flow in the flow duct by such ribs,the central body can also be positioned and held in place via the guidevane tips. As shown in FIG. 8, radially directed holes 441 can beincorporated in the central body 44 for this purpose, and shanks 16specially designed for this purpose on the vane tips engage in saidholes 441. This device having the guide vanes arranged radially aroundthe central body also permits simplified fitting of the guide vanes,which can already be arranged around the central body 44 beforeinsertion into one of the two casing parts 41 or 42. The unit consistingof central body and all the guide vanes can then be directed in a singleoperation to the place intended for it.

Of course, corresponding holes may also be provided in the exemplaryembodiment having a central body positioned and held by means of aretaining rib. They also serve in this case for simplified fitting bythe guide vanes having the special vane tip shanks being inserted intothe holes in the central body before they are then placed in theradially running apertures in the one casing part.

The vane tip shanks described may be fixedly connected to the tips ofthe guide vanes or else they may be rotatably mounted in holes providedfor this purpose in the vane tips. In the second case, the shanks mayalso be fixedly connected to the central body, such that, during thefitting, the guide vanes can be slipped with their holes at the vanetips onto the shanks.

Of course, an exemplary embodiment of the guide device without a centralbody and having guide vanes running right into the center is alsopossible.

It will be appreciated by those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. The presently disclosedembodiments are therefore considered in all respects to be illustrativeand not restricted. The scope of the invention is indicated by theappended claims rather than the foregoing description and all changesthat come within the meaning and range and equivalence thereof areintended to be embraced therein.

LIST OF DESIGNATIONS

-   10 Guide vane-   11 Vane profile-   12 Vane shank-   13 Adjusting lever for moving the guide vanes-   14 Ball head-   15 Pin-   16 Vane tip shank for centering the central body and holding it in    place-   17 Shaft projection for the axial mounting of the guide vane-   20 Sliding shoe-   21 Sliding cylinder-   30 Adjusting ring for moving the guide vanes via the adjusting lever-   31 Annular groove for accommodating the sliding shoe-   32 Annular hole for accommodating the sliding cylinder-   40 Casing-   41, 42 Casing parts-   43 Retaining rib-   44 Central body-   441 Hole for accommodating the vane tip shank-   45 Aperture in the casing for accommodating the vane shank-   46 Hole for joining the casing parts-   47 Bearing element for the axial mounting of the adjusting ring-   48 Bearing element for the radial mounting of the adjusting ring-   49 Radial projections in the region of the aperture in the casing    for the axial mounting of the guide vane

1. A preswirl guide device for generating a preswirl in the intakeregion of a compressor, having guide vanes which are pivotable about arespective vane shank connected to the guide vane, having a pivotableadjusting ring, and having adjusting levers for transmitting torque fromthe adjusting ring to the vane shank of each guide vane, wherein thevane shank and the adjusting lever of the respective guide vanes are ofone-piece design.
 2. The preswirl guide device as claimed in claim 1,wherein the adjusting lever of each guide vane comprises a cylindricalpin which is guided in such a way as to be rotatable about its axis anddisplaceable along its axis in a hole of a cylindrical transmissionelement, the transmission element being guided in such a way as to berotatable about its axis and displaceable along its axis in a hole ofthe adjusting ring.
 3. The preswirl guide device as claimed in claim 1,wherein the adjusting lever of each guide vane comprises a hole in whicha pin projecting radially from a cylindrical transmission element isguided, the transmission element being guided in such a way as to berotatable about its axis and displaceable along its axis in a hole ofthe adjusting ring.
 4. The preswirl guide device as claimed in claim 1,wherein the adjusting lever of each guide vane has an end which isdesigned like a ball head and which is guided in a groove of theadjusting ring, the groove having walls which run parallel to oneanother and between which the ball head of the adjusting lever isguided.
 5. The preswirl guide device as claimed in claim 4, wherein theball head is rotatably guided in a ball socket of a transmissionelement, and in that the transmission element is displaceable along thewalls running parallel to one another.
 6. The preswirl guide device asclaimed in claim 1, wherein a casing in which the guide vanes arerotatably mounted is comprised of at least two parts joined together inthe region of the bearings of the guide vanes.
 7. The preswirl guidedevice as claimed in claim 1, wherein projections extending radiallywith respect to the axis of rotation of the guide vanes are arranged onthe vane shank and on the casing surrounding the vane shank, aprojection of the vane shank and a projection of the casing engaging oneinside the other for the axial mounting of the respective guide vane. 8.The preswirl guide device as claimed in claim 1, wherein with respect tothe axis of rotation of the guide vane, a radially oriented groove isincorporated in the vane shank and/or in the casing surrounding the vaneshank, which groove, for the axial mounting of the guide vane, interactswith a projection, extending radially with respect to the axis ofrotation of the guide vane and engaging in the groove, and/or with abearing ring.
 9. The preswirl guide device as claimed in claim 1,wherein a central body is arranged in the region of the tips of theguide vanes arranged radially about an axis.
 10. The preswirl guidedevice as claimed in claim 9, wherein shanks formed on the vane tips arerotatably mounted in radially oriented holes of the central body. 11.The preswirl guide device as claimed in claim 9, wherein the centralbody is fastened to an external casing part via at least one retainingrib directed radially outward.
 12. The preswirl guide device as claimedin claim 10, wherein shanks formed on the vane tips are rotatablymounted in radially oriented holes of the central body.
 13. A compressorcomprising a preswirl guide device as claimed in claim
 1. 14. An exhaustgas turbocharger comprising a compressor having a preswirl guide deviceas claimed in claim
 1. 15. The preswirl guide device as claimed in claim5, wherein a casing in which the guide vanes are rotatably mounted iscomprised of at least two parts joined together in the region of thebearings of the guide vanes.
 16. The preswirl guide device as claimed inclaim 5, wherein projections extending radially with respect to the axisof rotation of the guide vanes are arranged on the vane shank and on thecasing surrounding the vane shank, a projection of the vane shank and aprojection of the casing engaging one inside the other for the axialmounting of the respective guide vane.
 17. The preswirl guide device asclaimed in claim 5, wherein with respect to the axis of rotation of theguide vane, a radially oriented groove is incorporated in the vane shankand/or in the casing surrounding the vane shank, which groove, for theaxial mounting of the guide vane, interacts with a projection, extendingradially with respect to the axis of rotation of the guide vane andengaging in the groove, and/or with a bearing ring.
 18. The preswirlguide device as claimed in claim 5, wherein a central body is arrangedin the region of the tips of the guide vanes arranged radially about anaxis.
 19. A compressor comprising a preswirl guide device as claimed inclaim
 5. 20. An exhaust gas turbocharger comprising a compressor havinga preswirl guide device as claimed in claim
 5. 21. A preswirl guidedevice for generating a preswirl in the intake region of a compressor,comprising: a guide vane having a shank; a pivotable adjusting ring; andan adjusting lever for transmitting torque from the adjusting ring tothe shank of the guide vane, wherein the shank and the adjusting leverare formed of one-piece.